Cryotherapeutic cooling helps reduce or prevent swelling and pain by decreasing electrical conduction velocity in nerves, decreasing cellular permeability, and causing capillary constriction. There are a variety of approaches to administering cryotherapy. For instance, it is well-known that tissue temperature may be reduced by convection (flowing air over a local area of skin), by evaporation (spraying a local area of skin with a highly volatile liquid), or by conduction (contacting a local area of skin with a solid, liquid, or gaseous medium having a temperature lower than that of skin tissue). Conductive cooling has been found to be advantageous in many applications because it is thought to be more readily controllable than other cooling techniques.
A conductive cooling source may be therapeutically helpful if secured in contact with a specified anatomical region under an assured pressure for a specified duration. On the other hand, a conductive cooling source may be therapeutically ineffective or even harmful if contact with the designated anatomical region and predetermined pressure are not assured. Furthermore, it is typically necessary that such a cooling source be affixed by semi-skilled personnel in accordance with medical instructions and removed easily for cleansing and re-use.
Ice bags, gel packs, chemical cold packs, immersion, and ice massage are the most common methods of conductive cooling, and each has advantages and disadvantages. For instance, the cooling effect of ice bags lasts an extended period of time, but typically the bags do not contour to the body's curves for maximum application. Cold gel packs can be frozen and refrozen, but may cool the skin too fast, and, like ice bags, they do not readily contour to the body's curved contours for maximum application. Chemical cold bags are a good first-aid approach for field or wilderness, but generally do not produce a therapeutic degree of cold. Immersion of limb extremities in icy water provides complete and concentrated cold exposure, but generally does not lend itself to other body areas because too much of the uninjured area is exposed to the cold. On the other hand, ice massage is easy to apply and focus on a particular, generally small anatomical area, but the cold tends not to penetrate deeply or last for a desired, extended period of time, and the patient is generally immobilized during the application of ice massage.
In addressing the demand for cold therapy products, the modern health care industry has significantly focused on gel technology. However, because the technology typically produces a gel that is a semi-solid, single mass, cold gel packs are limited in their ability to conform easily to the injured part of the body for maximum application. The industry has attempted to mitigate this limitation through innovations in packaging that enhances body fit.
Typically, these cold packs have often been in the form of a bandage, compress or other local overlay having cooling gel compartments, anchoring straps mounted in a predetermined position, and a plurality of mating fasteners on the body of the overlay and at free ends of the straps. The purpose of this arrangement is to meet a variety of physical and anatomical conditions, although in practice, only a limited number of these conditions have been concurrently achieved in the past. In some devices of this type, the mating fasteners take the form of patches of hook and loop mating surfaces. Often such cold packs are not sufficiently conformable to the body to yield a snug, comfortable and reliable contact with the tissue for effective conduction from the cooling gel to the intended anatomical region.
The value of gel cold packs is further limited by the fact that they do not typically remain cold enough for the length of time required for effective application of cold therapy, especially if the patient's injury is acute. Additionally, the ability to reuse a gel cold pack is of no value if the packs are damaged or lost. Consequently, gel cold packs are cost-prohibitive in situations in which they are used in great numbers and are unlikely to be returned, such as when treating athletes' injuries after a sporting event has taken place.